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Multiple sensor multifrequency eddy current monitor for solidification and growth

Author:
Wallace, John
Published:
May 1, 1990.
Physical Description:
1 electronic document
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Summary:
A compact cylindrical multisensor eddy current measuring system with integral furnace was develop to monitor II-VI crystal growth to provide interfacial information, solutal segregation, and conductivities of the growth materials. The use of an array of sensors surrounding the furnace element allows one to monitor the volume of interest. Coupling these data with inverse multifrequency analysis allows radial conductivity profiles to be generated at each sensor position. These outputs were incorporated to control the processes within the melt volume. The standard eddy current system functions with materials whose electric conductivities are as low as 2E2 Mhos/m. A need was seen to extend the measurement range to poorly conducting media so the unit was modified to allow measurement of materials conductivities 4 order of magnitude lower and bulk dielectric properties. Typically these included submicron thick films and semiinsulating GaAs. This system was used to monitor complex heat transfer in grey bodies as well as semiconductor and metallic solidification.
Other Subject(s):
Collection:
NASA Technical Reports Server (NTRS) Collection.
Note:
Document ID: 19910012049.
Accession ID: 91N21362.
JPL, Proceedings of the First Workshop on Containerless Experimentation in Microgravity; p 357-36.
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No Copyright.
View MARC record | catkey: 15681648